Neuroethology and life history adaptations of the elasmobranch electric sense.
TL;DR: It is argued that the ontogenetic and seasonal variation in electrosensory tuning represent an adaptive electrosENSory plasticity that may be common to many elasmobranchs to enhance an individual's fitness throughout its life history.
Abstract: The electric sense of elasmobranch fishes (sharks and rays) is an important sensory modality known to mediate the detection of bioelectric stimuli. Although the best known function for the use of the elasmobranch electric sense is prey detection, relatively few studies have investigated other possible biological functions. Here, we review recent studies that demonstrate the elasmobranch electrosensory system functions in a wide number of behavioral contexts including social, reproductive and anti-predator behaviors. Recent work on non-electrogenic stingrays demonstrates that the electric sense is used during reproduction and courtship for conspecific detection and localization. Electrogenic skates may use their electrosensory encoding capabilities and electric organ discharges for communication during social and reproductive interactions. The electric sense may also be used to detect and avoid predators during early life history stages in many elasmobranch species. Embryonic clearnose skates demonstrate a ventilatory freeze response when a weak low-frequency electric field is imposed upon the egg capsule. Peak frequency sensitivity of the peripheral electrosensory system in embryonic skates matches the low frequencies of phasic electric stimuli produced by natural fish egg-predators. Neurophysiology experiments reveal that electrosensory tuning changes across the life history of a species and also seasonally due to steroid hormone changes during the reproductive season. We argue that the ontogenetic and seasonal variation in electrosensory tuning represent an adaptive electrosensory plasticity that may be common to many elasmobranchs to enhance an individual's fitness throughout its life history.
Citations
More filters
TL;DR: It is suggested that temperature plays an important role in the regulation of testosterone, and may serve as an ultimate cue for reproduction in male round stingrays.
Abstract: This study characterizes the seasonal reproductive cycle of male round stingrays (Urobatis halleri) in Seal Beach, California. Mature round stingrays were collected monthly by beach seine near the San Gabriel River outfall from August 2004-September 2006, and rays were assessed for gametogenesis and steroid hormone levels. Male round stingrays exhibit a seasonal pattern of increased gonadosomatic index (GSI), spermatogenesis, and production of testosterone (T) and 11-ketotestosterone (11-KT). Based on GSI, the male reproductive cycle was broken into three distinct phases. TUNEL positive staining was only observed in the Sertoli cells of mature spermatocysts during the degenerative testicular phase, suggesting that Sertoli cell death potentially plays a role in testicular degeneration and the regulation of sperm release. GSI, T, and 11-KT were all inversely correlated with daylength, while only T was inversely correlated with temperature. Captive male round stingrays subjected to water temperatures of 25 degrees C showed a significant decrease in plasma testosterone concentrations, but the same males exposed to ambient water temperatures (18 degrees -20 degrees C) exhibited T concentrations observed in wild male round stingrays during the recrudescent phase. Together, these findings suggest that temperature plays an important role in the regulation of testosterone, and may serve as an ultimate cue for reproduction in male round stingrays.
45 citations
Cites background from "Neuroethology and life history adap..."
...Mating occurs over a contracted period of time in other populations of U. halleri (Nordell, 1994; Sisneros and Tricas, 2002), and based on the rapid decline in T following the March surge to quiescent phase concentrations, this is likely the case in the Seal Beach population....
[...]
...halleri (Nordell, 1994; Sisneros and Tricas, 2002), and based on the rapid decline in T following the March surge to quiescent phase concentrations, this is likely the case in the Seal Beach population....
[...]
TL;DR: Current understanding of ored construction, operation and decommissioning with regard to the potential interaction with elasmobranchs is discussed and a framework is proposed which aims to promote cooperative initiatives between elasmOBranch conservation management and the offshore renewables industry.
Abstract: the uk government's strategy for reducing greenhouse gas emissions to meet carbon mitigation obligations and the wider aims on sustainable development has provided the impetus for a rapid growth in activity associated with offshore renewable energy, particularly offshore wind farms. recently, consents for offshore renewable energy development (ored) were approved in three strategic areas—the outer thames estuary, the greater wash and the eastern irish sea. the scale of the planned developments means that each will have a large environmental footprint and multiple ored will have a cumulative effect on the environment. here we discuss current understanding of ored construction, operation and decommissioning with regard to the potential interaction with elasmobranchs because of the worrying status of elasmobranch populations within the uk coastal zone. based on the likely interactions between elasmobranchs and ored a framework is proposed which aims to promote cooperative initiatives between elasmobranch conservation management and the offshore renewables industry.
40 citations
01 Jun 2013-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: The morphology, function and origin of the electroreceptors in the two aquatic species, the platypus and the Guiana dolphin, are reviewed: both species search for prey animals in low-visibility conditions or while digging in the substrate, and sensory thresholds are within one order of magnitude.
Abstract: Passive electroreception is a sensory modality in many aquatic vertebrates, predominantly fishes. Using passive electroreception, the animal can detect and analyze electric fields in its environment. Most electric fields in the environment are of biogenic origin, often produced by prey items. These electric fields can be relatively strong and can be a highly valuable source of information for a predator, as underlined by the fact that electroreception has evolved multiple times independently. The only mammals that possess electroreception are the platypus (Ornithorhynchus anatinus) and the echidnas (Tachyglossidae) from the monotreme order, and, recently discovered, the Guiana dolphin (Sotalia guianensis) from the cetacean order. Here we review the morphology, function and origin of the electroreceptors in the two aquatic species, the platypus and the Guiana dolphin. The morphology shows certain similarities, also similar to ampullary electroreceptors in fishes, that provide cues for the search for electroreceptors in more vertebrate and invertebrate species. The function of these organs appears to be very similar. Both species search for prey animals in low-visibility conditions or while digging in the substrate, and sensory thresholds are within one order of magnitude. The electroreceptors in both species are innervated by the trigeminal nerve. The origin of the accessory structures, however, is completely different; electroreceptors in the platypus have developed from skin glands, in the Guiana dolphin, from the vibrissal system.
39 citations
Cites background from "Neuroethology and life history adap..."
...2008), lungfish (Jørgensen 2011) and amphibians (Fritzsch and Münz 1986), as well as on the pectoral fins in batoids (Raschi 1986; Sisneros and Tricas 2002)....
[...]
...…electroreceptors are mainly located in the head region, but are also found on the trunk in teleosts (Whitehead et al. 1999; Hollmann et al. 2008), lungfish (Jørgensen 2011) and amphibians (Fritzsch and Münz 1986), as well as on the pectoral fins in batoids (Raschi 1986; Sisneros and Tricas 2002)....
[...]
TL;DR: The Earth has always been a changeable place but now warming trends shift seasons and storms occur with greater frequency, intensity and duration, which has prompted reference to the modern era as the Anthropocene caused by human activity.
36 citations
Cites background from "Neuroethology and life history adap..."
...Electrical: Weakly electric fish communicate via electrical signals that are also used in courtship, for territorial behavior and are influenced by hormones (Bass and Hopkins, 1985; Sisneros and Tricas, 2002; Bullock et al., 2005)....
[...]
TL;DR: It is proposed that these sensory adaptations support amplified indiscriminate signal detection in sharks compared with selective frequency detection in skates, potentially reflecting the electroreceptive requirements of these elasmobranch species.
Abstract: Ancient cartilaginous vertebrates, such as sharks, skates and rays, possess specialized electrosensory organs that detect weak electric fields and relay this information to the central nervous system1–4. Sharks exploit this sensory modality for predation, whereas skates may also use it to detect signals from conspecifics
5
. Here we analyse shark and skate electrosensory cells to determine whether discrete physiological properties could contribute to behaviourally relevant sensory tuning. We show that sharks and skates use a similar low threshold voltage-gated calcium channel to initiate cellular activity but use distinct potassium channels to modulate this activity. Electrosensory cells from sharks express specially adapted voltage-gated potassium channels that support large, repetitive membrane voltage spikes capable of driving near-maximal vesicular release from elaborate ribbon synapses. By contrast, skates use a calcium-activated potassium channel to produce small, tunable membrane voltage oscillations that elicit stimulus-dependent vesicular release. We propose that these sensory adaptations support amplified indiscriminate signal detection in sharks compared with selective frequency detection in skates, potentially reflecting the electroreceptive requirements of these elasmobranch species. Our findings demonstrate how sensory systems adapt to suit the lifestyle or environmental niche of an animal through discrete molecular and biophysical modifications. Shark and skate electrosensory cells use specific potassium channels to support either indiscriminate detection of electrical stimuli or selective frequency tuning, respectively, demonstrating adaptation of sensory systems through discrete molecular modifications.
35 citations
References
More filters
7,158 citations
882 citations
Journal Article•
TL;DR: This is a comprehensive identification guide encompassing all shallow marine fishes within California waters, and many of the family keys have been revised to incorporate recent taxonomic changes and to clarify previously ambiguous terminology.
Abstract: This is a comprehensive identification guide encompassing all shallow marine fishes within California waters. Geographic range limits, maximum size, depth range, a brief color description, and some meristic counts including, if available: fin ray counts, lateral line pores, lateral line scales, gill rakers, and vertebrae are given. Body proportions and shapes are used in the keys and a statement concerning the rarity or commonness in California is given for each species. In all, 554 species are described. Three of these have not been recorded or confirmed as occurring in California waters but are included since they are apt to appear. The remainder have been recorded as occurring in an area between the Mexican and Oregon borders and offshore to at least 50 miles. Five of California species as yet have not been named or described, and ichthyologists studying these new forms have given information on identification to enable inclusion here. A dichotomous key to 144 families includes an outline figure of a representative for all but two families. Keys are presented for all larger families, and diagnostic features are pointed out on most of the figures. Illustrations are presented for all but eight species. of the 554 species, 439 are found primarily in depths less than 400 ft., 48 are meso- or bathypelagic species, and 67 are deepwater bottom dwelling forms rarely taken in less than 400 ft. depth. The deepwater forms included are those taken in commercial trawling gear or that occasionally occur near the surface. An illustrated glossary is included to facilitate use of the identification keys and species descriptions. A comments section presents in detail reasons for certain taxonomic choices and to acknowledge personal communications. Original data presented include a ventral sensory pore pattern key for the skates, 170 geographic range limit extensions, and several depth range and maximum size records. Many of the family keys have been revised to incorporate recent taxonomic changes and to clarify previously ambiguous terminology.
667 citations
TL;DR: This volume constitutes a series of invited chapters based on presentations given at an International Conference on the Sensory Biology of Aquatic Animals held June 24-28, 1985 at the Mote Marine Laboratory in Sarasota, Florida.
Abstract: This volume constitutes a series of invited chapters based on presentations given at an International Conference on the Sensory Biology of Aquatic Animals held June 24-28, 1985 at the Mote Marine Laboratory in Sarasota, Florida. The immediate purpose of the conference was to spark an exchange of ideas, concepts, and techniques among investigators concerned with the different sensory modalities employed by a wide variety of animal species in extracting information from the aquatic environment. By necessity, most investigators of sensory biology are specialists in one sensory system: different stimulus modalities require different methods of stimulus control and, generally, different animal models. Yet, it is clear that all sensory systems have principles in common, such as stimulus filtering by peripheral structures, tuning of receptor cells, signal-to-noise ratios, adaption and disadaptation, and effective dynamic range. Other features, such as hormonal and efferent neural control, circadian reorganization, and receptor recycling are known in some and not in other senses. The conference afforded an increased awareness of new discoveries in other sensory systems that has effectively inspired a fresh look by the various participants at their own area of specialization to see whether or not similar principles apply. This inspiration was found not only in theoretical issues, but equally in techniques and methods of approach. The myopy of sensory specialization was broken in one unexpected way by showing limitations of individual sense organs and their integration within each organism. For instance, studying vision, one generally chooses a visual animal as a model.
664 citations